Critical Reasoning

It is important for children, who are the leaders of the future , to know how the govt of their country works.
Therefore, children should be taught the history of their country and how its government was formed.

Which of the following, if true, most weakens the argument above?

A. Every person who knows how the govt of a country works, knows how the govt was formed
B. Only people who know how a country's govt was formed, know how it works
C. most people who know how a country's govt was formed, know how its govt works
D. Some people who know how a country's govt works do not know how its govt was formed.
E. Some methods of teaching about the history of a country are less effective than the others

Source : Kaplan..

Am baffled!!!
Can someone help out with this? The reasoning provided by kaplan was too brief for my understanding.
Will post the OA when i get some replies . (Sorry for that)

I will go with D

the question stem has an assumption that children have to know how government was formed to understand how its government works

A. supports the assumption ..incorrect
B. supports the assumption ..incorrect
C. supports the assumption ..incorrect
D. Only option which says that to know how government works children does not have to know how government was formed--correct
E. irrelevant

what is OA?

thanks Liferocks. I also applied similar reasoning later on but in the first try I was a bit baffled by the question.
OA is D. So you are right.

I applied below reasoning... guess it brings us to answer D.

Premise : you should know how govt was formed
Conc : then you will know how it works
Or : Only if you know how it was formed, then you can know how the govt works.
Weakening factor : if you know how a country works without knowing how it was formed, then it weakens the conclusion.

I believe the correct answer should be D